A device that can limit the maximum amount of deformation of the suspension. It reduces the direct impact of the axle on the frame (or body) and prevents excessive deformation of the elastic element. The buffer block is composed of rubber blocks, steel plates and bolts. Some buffer blocks are made of porous polyurethane and are hollow inside. Most of the cushion blocks of modern cars are made of porous polyurethane materials, and rubber materials are gradually replaced by them. The porous buffer block made of polyurethane material has the following advantages that cannot be replaced by rubber: the mass is small, about 1/2 of the deformation of the rubber buffer block of the same size, and it has good nonlinear characteristics.